Insights into the Combined Effects of Environmental Concentration of Difenoconazole and Tebuconazole on Zebrafish Early Life Stage

Limited literature had focused on the combined effect of triazole fungicides on aquatic organisms at environmental concentrations. In this research, transcriptomics and metabolomics demonstrated DIF and TEB mixtures at different concentrations simultaneously influenced the lipid metabolism, arachidonic acid metabolism, steroid hormone biosynthesis and tryptophan metabolism, but showed diverse response patterns mediating the combined effects on embryos after 120 h exposure. The DIF and TEB mixture at aquatic life benchmark caused combined effect on yolk sac resorption and metabolites was less than the additive effect of individual DIF and TEB. While their mixture at environmental concentration caused synergistic effect on the accumulation of metabolites in metabolic pathways, which might cause more adverse effects on growth in zebrafish later life stages. Results further demonstrated that addition of arachidonic acid increased the transcripts of Pla2, Ptgs1, Cyp19a and Cxcl8b, allayed the accumulation of PLA2 and 17β-E2, and induced more PGF2α, IFN and IL6 levels in zebrafish larvae, indicated arachidonic acid metabolism might have important regulatory roles in hormone synthesis and immune response. Current results indicated more attention should been paid to the environmental concentration, it is crucially important to consider the mixture effects at different concentrations, combinations and developmental stages